Tread grinding wheel

ABSTRACT

A tire tread grinding wheel comprising a pair of hub sections having peripheral wedging flanges on which there is mounted an expandable collet having a separable abrading band. The hub sections include orientation and aligning means permitting assembly and disassembly of the wheel unit either on or separate from the grinding equipment. The wedging flanges are ground so that the collar and thereby the abrading sleeve is forced into true round as the hub segments are drawn into secured relationship.

United States Patent Waller et a1.

July 1, 1975 TREAD GRINDING WHEEL Inventors: Gustav M. Waller, Geneva; Kenneth L. Landmark, St. Charles, both of 111.

Amsted Industries Incorporated, Chicago, 1117 Filed: July 22, 1974 Appl. No.: 490,684

Assignee:

US. Cl. .1 51/372; 51/372; 51/375 Int. Cl. B24d 9/02 Field of Search 51/358. 372-375 References Cited UNITED STATES PATENTS 7/1928 Howland 51/375 6/1937 Price 51/372 10/1972 Landmark 51/372 FOREIGN PATENTS OR APPLICATIONS 435.857 9/1935 United Kingdom 51/372 1.336,833 7/1963 France 1. 51/372 Primary Examiner-Owe M. Simpson I 57] ABSTRACT A tire tread grinding wheel comprising a pair of hub sections having peripheral wedging flanges on which there is mounted an expandable collet having a separable abrading band. The hub sections include orientation and aligning means permitting assembly and disassembly of the wheel unit either on or separate from the grinding equipment. The wedging flanges are ground so that the collar and thereby the abrading sleeve is forced into true round as the hub segments are drawn into secured relationship.

'7 Claims, 4 Drawing Figures TREAD GRINDING WHEEL BACKGROUND AND SUMMARY OF THE INVENTION The balancing of automobile tires since the advent of the radial tire has assumed ever greater importance. One method of achieving balance is by grinding the treads to obtain a uniform and constant cross-section through the tire.

Conventional tire grinding wheel equipment has been found unsatisfactory to achieve the precision grinding required. Heretofore, the grinding wheel equipment has generally been constructed with the wheel as an integral unit. These integral grinding wheels must be discarded or reworked in their entirety after the grinding surface becomes worn. Other grinding wheel structures, as exemplified by U.S. Pat. No. 3,698,14l, provide replaceable grinding sleeves, but these prior structures have been deficient because the grinding surfaces frequently are out of round. As a result. variations in the depth of grind occurs about the periphery of the tread so that the tire is improperly balanced. Also these out of round wheels cause wear on the grinding equipment itself so that grinding equipment is subject to breakdown.

One structure for overcoming these difficulties is described in copending application Ser. No. 43l,l l5, filed .Ian. 1, I974, and assigned to the assignee of the present invention.

The grinding wheel assembly of the aforesaid application comprises a pair of cylindrical hub sections of which one hub section is formed with a boss on which the other hub section is supported and oriented thereon. Each of the hub sections is formed with oppositely tapered cylindrical flanges of which the respective circumferences are formed so as to be in true round about the axis of rotation of the wheel. A sleeve having an abrading surface is wedgingly retained on the tapered flanges in a true round condition when the hub sections are assembled.

By the present, it is proposed to improve the above described structure by providing a separable abrading surface. To this end the sleeve is formed to function in the nature of a collet, which expands when wedged on the flanges. A separable abrading collar is frictionally retained on the collet when the latter is wedged on the hub.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of grinding wheel assembly incorporating the structure of the present invention.

FIG. 2 is a cross-section, a view taken generally along the lines 2-2 of FIG. 1 showing details of the grinding wheel assembly.

FIG. 3 is a fragmentary front elevational view of the collet.

FIG. 4 is a perspective view of the abrading collar.

Referring now to the drawings, the grinding wheel assembly l embodying the structure of the present invention is fixed for rotation with a drive shaft 11. The drive shaft 11 is formed with a projecting peripheral fastening flange l2 spaced inwardly from the terminal end thereof.

The grinding wheel assembly includes an inner or first hub section 13 and an outer or a second hub section 14. The inner hub section 13 includes a circular web 15 having a generally horizontally projecting peripheral flange 16. An axial bore 17 accommodates the end of the shaft 11 and a circular recess 18 in the web 14 receives the peripheral flange 12 Threaded through a central hub portion 19 of the inner hub section 13 and into the fastening flange 12 are a plurality of angularly spaced bolts 20 which serve to fasten the inner hub section for rotation with the shaft 11.

The peripheral flange 16 is formed to provide a rim or wedging face 21 which is tapered outwardly from the web 15 preferably at an angle of about 9 relative to the longitudinal axis of the shaft as shown in FIG. 2. The flange 16 is generally rigid so as to provide a wedge as more fully to be explained hereinafter.

The outer hub section 14 includes a circular web 22 having an axial or central opening 23 which receives the axial boss 19 on the inner hub section 13. The axial boss 19 serves to maintain the inner and outer holes in axial alignment. A generally horizontally projecting peripheral flange 24 is formed about the periphery of the web 22. The web 22 is complementary to the web 15 so that the inner and outer hub sections 13 and 14 form complementary hubs of the grinding wheel 10 as shown.

The inner and outer hub sections 13 and 14 are fastened together by a plurality of angularly spaced bolts 25 which are radially spaced outwardly from the boss 19. The bolts 25 slide through openings 26 in the outer hub section 14 and threaded into openings 27 in the inner section 13 so that the hub sections 13 and 14 are drawn together. This permits the wedging or caming action at the wedging faces more fully to be described hereinafter. A dowel 28 is snugly seated within an aperture and a hole formed in the inner and outer web 13 and 14 respectively. The dowel 28 serves to maintain the hub sections in the same angular orientation upon disasembly and reassembly thereof.

The peripheral flange 24 of the outer hub section 14 also includes a rim or wedging face 31 which is sloped upwardly and outwardly in opposing relationship to the sloped wedging face 21 on the flange 16. The wedging face 31 is preferably sloped at an angle of about 9 relative the longitudinal axis of the drive shaft 11.

The two hub sections 13 and 14 are assembled by sliding the boss 19 into the opening 23. In this manner the boss serves to maintain axial alignment of the hub sections 13 and 14. Thereafter the dowel 28 is inserted to maintain the hub sections in predetermined angular orientation. Bolts 25 are then inserted to secure the hub sections 13 and 14 together. In the assembled condition, the hub sections form a rigid grinding wheel assembly 10 having the rims 21 and 31 tapering in opposite directions to form a shallow V-shaped periphery. The rim or wedging faces 21 and 31 are then precision ground to achieve a true roundness about the longitudinal axis and to assure that the taper along the entire width of the flanges is uniform. At the same time, the wheel 10 is balanced in the assembled condition.

A collet 32 is securely fastened by wedging on the tapered surfaces 18 and 31 caused by the clamping action of the inner and outer hub sections 13 and 14 toward each other. To this end. the inner circumference of the collet 32 is provided with two sloped surfaces 33 and 34 inclined at substantially the same angle as the wedging faces 21 and 31 on the inner and outer hub sections 13 and 14. A plurality of angularly spaces slits 34 may be provided in the collet 32 as shown for example in FIG. 3. The slits 34 permit limited expansion of the collet 32 during assembly on the grinding wheel.

A separable abrading band or loop 36 as shown in FIG. 4 is frictionally retained on the face or outer periphery of the collet 32 when the inner and outer hub sections 13 and M are assembled. The abrading band 36 is made from a mild steel and a tungsten carbide grit 37 is deposited on the outer face thereof. As a result of the tightening of the bolts the tapered wedging surfaces 21 and 31 are operative to wedgingly engage the collet 32 and expand the same. As the collet 32 expands, the abrading loop or band 36 which is of fixed diameter is frictionally retained on the periphery of the wheel assembly 10.

With the foregoing structure, when the abrading surface becomes worn, it is merely necessary to unloosen the bolts so that the inner and outer hub sections 13 and 14 are spaced apart whereupon the collet 32 may contract and release the abrading band 36 so that it may be removed and replaced with a band having a replenished abrading surface.

What is claimed is:

l. A grinding wheel assembly for a tire tread grinding apparatus having a drive shaft, said grinding wheel assembly comprising a first hub section, first fastening means for directly fastening said first hub section to the drive shaft for rotation therewith. a second hub section, second fastening means for fastening said second hub section only to said first hub section, each of said fastening means being exposed and accessible for independent disassembly, complementary aligning and orientating means for axially aligning and angularly orienting said first and second hub sections thereby to maintain said hub sections in the same alignment and orientation upon reassembly of said hub sections after said hub sections are disassembled, said hub sections each having oppositely directed peripheral flanges having tapered wedging surfaces, said tapered wedging surfaces being formed to provide a circumference in true round about the axis of rotation of the drive shaft. and an expansible collet mounted on said wedging surface and an abrading band of fixed diameter frictionally retained on said collet when said fastening means are drawn tight to fasten said first hub section and said second hub sections thereby to wedgingly expand said collet.

2. The invention as defined in claim 1 wherein said aligning means comprises an axial boss on said first hub section and an axial opening on said second hub section in which said boss is received.

3. The invention as defined in claim 1 wherein said angular orientation means comprises a dowel seated in said first and second hub sections.

4. The invention as defined in claim 3 wherein said second fastening means is radially spaced from said axial boss.

5. The invention as defined in claim 4 wherein said first fastening means for fastening said first hub section to the drive shaft extend through said boss.

6. The invention as defined in claim 4 wherein the inside circumference of said collet is tapered complementary to the taper of said flanges.

7. The invention as defined in claim 6 wherein said taper of said flanges converges at an angle of about 9 with the longitudinal axis of the wheel. 

1. A grinding wheel assembly for a tire tread grinding apparatus having a drive shaft, said grinding wheel assembly comprising a first hub section, first fastening means for directly fastening said first hub section to the drive shaft for rotation therewith, a second hub section, second fastening means for fastening said second hub section only to said first hub section, each of said fastening means being exposed and accessible for independent disassembly, complementary aligning and orientating means for axially aligning and angularly orienting said first and second hub sections thereby to maintain said hub sections in the same alignment and orientation upon reassembly of said hub sections after said hub sections are disassembled, said hub sections each having oppositely directed peripheral flanges having tapered wedging surfaces, said tapered wedging surfaces being formed to provide a circumference in true round about the axis of rotation of the drive shaft, and an expansible collet mounted on said wedging surface and an abrading band of fixed diameter frictionally retained on said collet when said fastening means are drawn tight to fasten said first hub section and said second hub sections thereby to wedgingly expand said collet.
 2. The invention as defined in claim 1 wherein said aligning means comprises an axial boss on said first hub section and an axial opening on said second hub section in which said boss is received.
 3. The invention as defined in claim 1 wherein said angular orientation means comprises a dowel seated in said first and second hub sections.
 4. The invention as defined in claim 3 wherein said second fastening means is radially spaced from said axial boss.
 5. The invention as defined in claim 4 wherein said first fastening means for fastening said first hub section to the drive shaft extend through said boss.
 6. The invention as defined in claim 4 wherein the inside circumference of said collet is tapered complementary to the taper of said flanges.
 7. The invention as defined in claim 6 wherein said taper of said flanges converges at an angle of about 9* with the longitudinal axis of the wheel. 